Number of subsets T of S={0,1,2,...,n-1} such that the closure of T under addition modulo n is S.

Terms

a(0) =1a(1) =1a(2) =4a(3) =5a(4) =16a(5) =22a(6) =64a(7) =109a(8) =283a(9) =486a(10) =1189a(11) =2174a(12) =5097a(13) =9528a(14) =21904a(15) =41549a(16) =92022a(17) =177043a(18) =387715a(19) =754910a(20) =1624543a(21) =3174095a(22) =6751375a(23) =13296454a(24) =27962241a(25) =55173405a(26) =115220461a(27) =228121892a(28) =472419049a(29) =937688232